68 RAPID POPULATION GROWTH-I
The kinds of environmental adversity that exist for the less developed countries result much more from rapid population growth combined with a lack of technology than from rising incomes and the presence of new technology. In agricultural areas, extension of cropping into rain-fed areas that are at best suitable only for grazing, and of grazing into areas that should not even be grazed—prevalent over much of the arid Middle East, for example-has led to extremely poor soil conditions, remediable in part by better management (e.g., controlled grazing) and new technology (scientific farming).
Many of the savannah or semi-desert areas . . . are the worst abused land resources and the resulting erosion presents a major problem requiring not only technical solutions but legal and social regulation of grazing use, a very difficult task to enforce in nomadic or semi-nomadic communities.*
Rapidly rising population aggravates this kind of resource pressure, as well as the pressure caused by a lack of cheap fuel, leading in many places to near-total gathering as fuel wood of any shrublike vegetation that might otherwise begin to take hold.
Large new engineering structures, especially dams and lakes, although permitting increased production also bring their share of ecological problems. Extension of waterborne diseases, of undesirable plant life (e.g., water hyacinths that clog water courses, transpire water to the atmosphere, etc.) are well known. The need for heavy fertilization and application of pesticides that are inescapable accompaniments of a Green Revolution set in motion other disturbances, some of limited spatial extent, some having more far-reaching consequences. The very rapid spread of new technology designed to feed rising populations may have secondary effects on the environment to a degree and an extent yet unknown. Worldwide alertness to these dangers in developing countries may provide the time and the incentive for timely coun-termeasures.
Many of the primary environmental problems of the high income countries, correlated with a high degree of industrialization, mechanized transport, and high fuel use, have not yet appeared in poorer countries and are not likely to show up for some time, given low income levels. Here again, the experience of the richer countries could provide useful indicators of impending trouble.
Finally certain environmental phenomena could, if continued, threaten the survival of man. They derive basically from alterations in certain ecological systems, brought about by man-made interference. Modifications in the heat balance of the earth, ocean oollution. effects of radioactive waste emission int—or expenditures for—the environment in ways that now preoccupy many people